A tip Of a screwdriver, conventionally used in an industrial field, is shown in FIG. 10. Conventionally, a screwdriver 100 is provided with a driver bit 110 having cross-shaped tips 111, 113 on both ends thereof. Only by switching the attachment direction of the driver bit 110 for use, the driver bit 110 can be durable twice as long as a driver bit having only one driver tip. The driver bit 110 normally has a hexagonal cross section, and peripheral groove portions 115 and 117 are formed, respectively, at a given interval in the axial direction of the driver bit 110. For attachment, the driver bit 110 is inserted in a hexagonal engagement hole 101 provided in a body 104 of the screwdriver 100, and a steel ball 103 is engaged with the peripheral groove portion 115 or 117 with an urging force applied by a leaf spring 102, such that the driver bit 110 is prevented from coming off the engagement hole 101. In addition, an exposed tip of the driver bit 110 is short, and can be manually extracted with difficulty from the engagement hole 101.
A plier or other tool is required for an operator to pull the driver bit 110 from the engagement hole 101.
Furthermore, while replacing the driver bit 110, the operator has to remove the adjustment sleeve 105 from the screwdriver 100 and put aside an adjustment sleeve 105. Therefore, the adjustment sleeve 105 might be lost on site.